On Thu, Mar 28, 2019 at 09:18:22AM -0500, Bjorn Helgaas wrote:

On Mon, Mar 25, 2019 at 08:43:19PM +0100, marek.vasut@gmail.com wrote:

...

From: Kazufumi Ikeda kaz-ikeda@xc.jp.nec.com

Reestablish the PCIe link very early in the resume process in case it went down to prevent PCI accesses from hanging the bus. Such accesses can happen early in the PCI resume process, as early as the SUSPEND_RESUME_NOIRQ step, thus the link must be reestablished in the driver resume_noirq() callback.

Fixes: e015f88c368d ("PCI: rcar: Add support for R-Car H3 to pcie-rcar")

I'm fine with the fix itself, but since e015f88c368d appeared more than two years ago in v4.5, the justification for merging this after the merge window is a little weak.

Is there a more recent change that exposed this problem? The usual situation is that we merged something during the v5.1 merge window that caused a regression, and we're now fixing that before v5.1 final.

I do not think that's urgent enough to merge it in one of the -rc* but I won't speak for the authors - it will trickle back anyway through the stable mechanism, I just queued it as a fix since that's how it qualifies.

So postponing it to v5.2 is fine by me, just let me know how it is best to handle it.

Thanks, Lorenzo

Bjorn

...

Signed-off-by: Kazufumi Ikeda kaz-ikeda@xc.jp.nec.com Signed-off-by: Gaku Inami gaku.inami.xw@bp.renesas.com Signed-off-by: Marek Vasut marek.vasut+renesas@gmail.com [lorenzo.pieralisi@arm.com: reformatted commit log] Signed-off-by: Lorenzo Pieralisi lorenzo.pieralisi@arm.com Reviewed-by: Simon Horman horms+renesas@verge.net.au Acked-by: Wolfram Sang wsa+renesas@sang-engineering.com Cc: stable@vger.kernel.org Cc: Geert Uytterhoeven geert+renesas@glider.be Cc: Phil Edworthy phil.edworthy@renesas.com Cc: Simon Horman horms+renesas@verge.net.au Cc: Wolfram Sang wsa@the-dreams.de Cc: linux-renesas-soc@vger.kernel.org

---

V2: - Use BIT() macro for (1 << n) - Since polling in rcar_pcie_wait_for_dl() uses udelay(), do not add extra changes to this function anymore - Make resume_noirq return early and clean up parenthesis therein V3: - Add missing PMSR register definition, dropped due to patch reshuffling

---

drivers/pci/controller/pcie-rcar.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+)

diff --git a/drivers/pci/controller/pcie-rcar.c b/drivers/pci/controller/pcie-rcar.c index c8febb009454..6a4e435bd35f 100644 --- a/drivers/pci/controller/pcie-rcar.c +++ b/drivers/pci/controller/pcie-rcar.c @@ -46,6 +46,7 @@ /* Transfer control */ #define PCIETCTLR 0x02000 +#define DL_DOWN BIT(3) #define CFINIT 1 #define PCIETSTR 0x02004 #define DATA_LINK_ACTIVE 1 @@ -94,6 +95,7 @@ #define MACCTLR 0x011058 #define SPEED_CHANGE BIT(24) #define SCRAMBLE_DISABLE BIT(27) +#define PMSR 0x01105c #define MACS2R 0x011078 #define MACCGSPSETR 0x011084 #define SPCNGRSN BIT(31) @@ -1130,6 +1132,7 @@ static int rcar_pcie_probe(struct platform_device *pdev) pcie = pci_host_bridge_priv(bridge); pcie->dev = dev;

• platform_set_drvdata(pdev, pcie);

err = pci_parse_request_of_pci_ranges(dev, &pcie->resources, NULL); if (err) @@ -1221,10 +1224,28 @@ static int rcar_pcie_probe(struct platform_device *pdev) return err; } +static int rcar_pcie_resume_noirq(struct device *dev) +{

• struct rcar_pcie *pcie = dev_get_drvdata(dev);
• if (rcar_pci_read_reg(pcie, PMSR) &&

•    !(rcar_pci_read_reg(pcie, PCIETCTLR) & DL_DOWN))
  

• return 0;
  

• /* Re-establish the PCIe link */
• rcar_pci_write_reg(pcie, CFINIT, PCIETCTLR);
• return rcar_pcie_wait_for_dl(pcie);

+}

+static const struct dev_pm_ops rcar_pcie_pm_ops = {

• .resume_noirq = rcar_pcie_resume_noirq,

+};

static struct platform_driver rcar_pcie_driver = { .driver = { .name = "rcar-pcie", .of_match_table = rcar_pcie_of_match,

• .pm = &rcar_pcie_pm_ops,
  

  .suppress_bind_attrs = true, }, .probe = rcar_pcie_probe,

-- 2.20.1